public class Example4_20{
    public static void main(String[] args) {
        char a[]={'a','b','c','D','E','F'};
        for (int i=0; i<a.length; i++){
            if(Character.isLowerCase(a[i]))
                a[i]=Character.toUpperCase(a[i]);
            else if(Character.isUpperCase(a[i]))
                a[i]=Character.toLowerCase(a[i]);
        }
        for(int i=0; i<a.length; i++)
            System.out.println(" "+a[i]);
    }
}